I believe when the bridge was renovated a few years before, it was re-enforced to be able to take the load of a tram. The approval to run a tram over it came la

I believe when the bridge was renovated a few years before, it was re-enforced to be able to take the load of a tram. The approval to run a tram over it came later. Similar thing happened with the subway that was never built. The station and a few tunnels where already dug because of renovations but the people voted no on building a subway. That part of HB turned into the SZU Station. The tram tunnels by the Tierspital where also meant for the subway from what I recall. When they converted those for the use with trams they had several issues like the tunnel being not heigh enough. You can see the tracks are very low and the electrical connection on top is almost completely compressed.